[Container-tools] How adb and Nulecule fit together?

[Tomas Kral]

On 02/04/2016 11:56 AM, Saleem Ansari wrote:
>> Subject: Re: [Container-tools] How adb and Nulecule fit together?
>>
>> Hi Saleem,
> 
> 
> Hi Tomas!
> 
> 
>>>
>>> Atomicapp is a reference implementation of Nulecule specification. However
>>> it doesn't define how to run the app itself, so I assume it is actually
>>> Atomic that will help with this task.
>>>
>>> However from the project description of Atomic: "Atomic Run Tool for
>>> installing/running/managing container images.", it doesn't say anything
>>> specific to Atomicapp either.
>>>
>>
>> Atomic is generic high-level tool for manipulating containers.
>>
>> Atomic allows an image provider to specify how a container image expects
>> to be run.
> 
> 
> This definitely helps me understand Atomic better. It also makes me ask more questions :-)
> 
>  * who is "image provider" here? ( can I as a developer be considered an image provider ? )
yes, basically whoever is building image ;-)

>  * does Atomic expect the containers to be described in a specific way?
Depends on what you mean by described in a specific way.
Atomic run,install and uninstall commands are using labels. If you want
to use them you need to build images with corresponding labels.

>  * can Atomic run any existing container image or the image has to be a specific RPM based distribution?
it can run any docker image

> 
> I am trying to understand the base facts/assumptions that are made by Atomic to work correctly.
> 
> 
>> You can build build Docker image with `RUN` label where you specify
>> command that is expected to be run to start this image.
>> Then when you run `atomic run <yourimage>`, Atomic first inspects image,
>> and if finds RUN label uses its value to start container.
>>
>> Atomic makes easier to run AtomicApp.
>> You can run AtomicApp without atomic (see:
>> https://github.com/projectatomic/atomicapp/blob/master/atomicapp.sh#L9)
>> But because this is a lot of parameters, it is easier to use atomic and
>> just do `atomic run <atomicappimage>`.
>> Atomic than reads RUN label from image and assemble full docker run
>> command
>> (https://github.com/projectatomic/atomicapp/blob/master/Dockerfiles.pkgs/Dockerfile.centos#L13)
>>
> 
> This example makes it super clear to me why Atomic exists. Kudos!
> 
>> Atomic cmd just makes running AtomicApp containers little easier that's
>> all :-) you can run AtomicApp even without it.
>>
>> Hope this helps ;-)
>>
>>
> 
> 
> Thanks!
> 
> Regards,
> Saleem
>